Recommend:
To the knowledge base

Setting up a public IPv4 subnet in the FRITZ!Box

The FRITZ!Box can also be used on an internet connection with multiple fixed ("static") public IPv4 addresses. This way you can offer your server services or internet applications in the internet under different public IP addresses.

Requirements / Restrictions

  • The internet service provider must supply you with a public IPv4 subnet for your internet connection. The FRITZ!Box uses the first IPv4 address of the IPv4 subnet for itself; the other IPv4 addresses can be used by devices in the home network.

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Setting up a public IPv4 subnet in the FRITZ!Box

  1. Click "Home Network" in the FRITZ!Box user interface.
  2. Click "Network" in the "Home Network" menu.
  3. Click on the "Network Settings" tab.
  4. Click the "IPv4 Addresses" button. If the button is not displayed, enable the Advanced View first.
  5. Enter the public IPv4 subnet that you received from your internet service provider in the "Prefix" and "Network mask" fields in the "Public IPv4 Subnet" section.
  6. Click "OK" to save the settings.

2 Configuring a network device

Adjust the IP settings on all of the network devices (for example the network adapter on the computer connected to the FRITZ!Box) that should be accessible at an IP address from the FRITZ!Box's public IPv4 subnet:

Note:Network devices that are assigned a public IP address no longer obtain their IP settings from the FRITZ!Box. Therefore, they cannot access other devices in the FRITZ!Box home network or the FRITZ!Box user interface.

  1. For the IP address, enter an IP address from the public IPv4 network. This IP address may not already be used by another device in the FRITZ!Box home network.
  2. For the subnet mask, enter the subnet mask that corresponds to the public IP address.
  3. If necessary, enter one of the internet service provider's default gateways as the default gateway.
  4. As the preferred and alternative DNS server, enter the DNS server of the internet service provider.

3 Setting up port sharing in the FRITZ!Box

Configure port sharing in the FRITZ!Box for the IP addresses from the public IPv4 subnet so that your server services or internet applications can be reached in the internet:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Permit Access" in the "Internet" menu.
  3. Click on the "Port Sharing" tab.
  4. Click "New Port Sharing".
  5. Select "Other applications" from the drop-down list "Port sharing enabled for".
  6. Enter a name of your choice for the port sharing rule in the "Name" field.
  7. Select the IP protocol (TCP, UDP, ESP or GRE) required by the server service or internet application from the drop-down list "Protocol".
  8. To enable port sharing for a single port, enter the number of the port used by the server service or internet application to accept connections in the "From port" and "through..." ("to port") fields.
    • To enable port sharing for a port range:
      1. In the "From port" field, enter the number of the first port used by the server service or internet application to accept connections, and in the "to port" field, enter the number of the last port.
      2. In the "to port" field, enter the number of the first port used by the server service or internet application to accept connections.
  9. Select "Enter the IP address manually" from the drop-down list "to computer".
  10. In the "to IP address" field, enter the public IP address that you assigned to the network device.
  11. Click "OK" to save the settings.